Creme Fraiche:
In a medium saucepan, over low heat, warm the cream to about 105 degrees F (40
degrees C). Remove from heat, transfer the cream to a bowl, and stir in the
buttermilk or plain yogurt. Let this mixture sit at room temperature
(70-75 degrees F) (21-24 degrees C), loosely covered with plastic wrap, until thickened
(like mayonnaise or thick yogurt) with a tangy, slightly nutty flavor.
(This
will take anywhere from 24 to
36 hours, depending on your room temperature.) When ready, stir the cream and then cover and place in the refrigerator until
well chilled (at least 8 hours, preferably overnight).
Creme fraiche
can be stored in the refrigerator for up to 10 days.

Creme Fraiche Frosting: Place your
mixing bowl and whisk in the freezer for about 15-30 minutes. Then
beat the Creme Fraiche with 1/2 teaspoon pure
vanilla extract and 1-2 tablespoons (15-25 grams) of granulated
white sugar, or to taste, until stiff peaks form. Can be used in desserts instead of whipped cream.